Timer0 is used by arduino for the millis and delay functions so is best left alone.There are library routines in the playground that give you access to timer interrupt functionality without having to understand the low level registers. See FrequencyTimer2 for one example.

Perhaps you might say what it is you want to do?

syrax

I solve the problem with AVR studio I think is better to use if you know how becouse the arduino code is BIGGER and little slow. My program is about 5K in pure C++ and have to write more code to finish my program . When i use direct access to register from arduino this make program smaller.

And last question is possible to remove from arduino millis and free this timer, asking becouse this is primitive time0 and is great from refreshing if you have display, buttons ... The idea is to run it on background and dont tnink it more in main code

Is the delay() use timer0 ? I use util/delay.h with no timers Regards from Bulgaria